Earth evolution, groundwater system, rock engineering and geohazards are related to rock mass structures of different scales. Due to the data deficiency on the structure of underground rock mass, it is a significant challenge to realize the regional elaborated analysis of rock mass structure. Based on the summary of research progress of multiscale rock mass structure investigation, in this study it lists the problems in the elaborated multiscale analysis of rock mass structure. Applying the theory of earth system science, the ideas and technical solutions for these problems are proposed. Rock mass structure is closely related to the evolution process and surrounding environment (pressure-temperature-time, PTt). It is necessary to explore the co-evolution mechanism of discontinuities on different scales and the elaborated analysis theory of multiscale rock mass structure from the perspective of system science. This study combines earth system science with modern survey, experiment, and simulation of rock mass, and proposes a multiscale research approach of rock mass structure combining "PTt -mechanical model-menergy dissipation-discontinuities". The approach is expected to realize the regional elaborated analysis of rock mass structure.